Automatic magnetic circuit-breaker.



No. 753,704. PATENTED MAR. l, 1904. F. 0. HARTMAN.

AUTOMATIC MAGNETIC CIRCUIT BREAKER.

APPLICATION FILED APR. 10, 1902.

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APPLICATION FILED APR. 10. 1902.

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AUTOMATIC MAGNETIC CIRCUIT BREAKER.

APPLICATION FILED APR.10. 1902.

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No. 753,704. PATENTED MAR. l, 1904. F. O. HARTMAN.

AUTOMATIC MAGNETIC CIRCUIT BREAKER.

APPLICATION FILED APR. 10. 1902.

N0 MODEL. 6 SHEETS-SHEET 4.

No. 753,704. PATENTED MAR. 1, 1904. I. O. HARTMAN.

AUTOMATIC MAGNETIC CIRCUIT BREAKER.

APPLICATION FILED APR. 10. 1902.

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T uowms DEL-Rs an m m Patented March 1, 1904.

PATENT OFFICE.

FRANK O. HARTMAN, OF MANSFIELD, OHIO.

AUTOMATIC MAGNETIC CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 753,704, dated March l,1904.

Application filed April 10, 1902. Serial No. 102,266. (No model.)

To aZZ whom it may concern:

Be it known that I, FRANK O. HARTMAN, a citizen of the United States,residing at Mansfield, in the county of Richland and State of Ohio, haveinvented certain new and useful Improvements in Automatic MagneticOircuit-Breakers, of which the following is a specification. 7

My invention relates to a double pole-circuit-breaker and one which canbe used as a single-pole circuit-breaker, if desired.

The primary object of my invention is to provide a means for regulatingthe current in an electric circuit in such a manner that when thecurrent exceeds a certain predetermined amount the circuit will bebroken and the flow of the current cut off.

Another object of my invention is to afford a means for reducing. orobviating arcing from the contact-pieces to the blocks when the circuitis broken, by submerging the operative mechanism of the circuit-breakerin an insulating liquid, such as oil, thereby practically eliminatingany tendency toward sparking.

It is also to be noted that by reason of thecontact of the insulatingliquid with such operative parts the mechanism is kept in perfectworking order, all friction caused by foreign substances Working intothe bearings, and the corrosion of the parts is obviated to a greatextent thereby. The insulating liquid also operates to prevent anyinjury to the operator otherwise liable to occur through arcing.

My circuit-breaker is adapted to be used in place of a non-automaticswitch.

My invention also consists in certain other details of construction andcombinations of parts, such as will be described more fully hereinafter,and particularly pointed out in the claims.

In the accompanying drawings, Figure I is a vertical cross-section of myimproved circuit-breaker. Fig. 2 is a vertical cross-section taken atright angles to Fig. 1. Fig. 3 is a longitudinal cross-section. Fig. iis a plan view of the upper portion of the circuit-breaker, the cover ofwhich is removed. Fig. 5 is a perspective view of my invention. Fig. 6is a detail view, partly in section, showing the laminated contact andconnected parts. Fig. 7 is a detail in front elevation of a bracketconnecting one end of the magnetic coil to the connecting-piece of thecircuit-breaker. Fig. 8 is rear perspective view of one of the laminatedcontacts. Figs. 9 and 10 are detail views in cross-section, showing themanner of securing the contact-blocks and the insulation. Fig. 11 is adetail in cross-section showing the manner of securing the casing andthe connecting-piece. Fig. 12 is a detail view, partly in section, ofthe latch-releasing mechanism. Fig. 13 is a detail view, in sideelevation, of the vertical shaft and the arms and springs securedthereto. Fig. 1 1 is a diagrammatic view of the electric circuit whenbroken and when complete. Fig. 15 is a view, partly in section, of amodification of the latch-releasing mechanism. Fig. 16 is a perspectivedetail view of the switch-arms and pivoted latches; and Fig. I? is a topplan view of the complete device, showing the manually-operated handlesfor actuating the switch-arms.

The framework of the circuit-breaker comprises'a bracket or table a,consisting of a flat plate, to the under face of which is secured thedeep box 5 of rectangular shape and to the upper face of which issecured a similarlyshaped cover I), which latter incloscs a smallerspace above the bracket or table. The box portion 6' of the casing orframework and the cover 5 are provided with flanges 1 1, between whichis received the table a, the three being secured together by means ofrivets or other suitable means, as shown. Between the point of junctureof the table and the box I) is interposed a packirg 2 for the purpose tobe hereinafter set forth.

The table or bracket (4 is provided with a hollow centrally-locateddepending portion 0, preferably made integral therewith. This dependingportion or post 0 extends nearly to the bottom of the box 6, and betweenthe ends 0 of the post and the bottom of box o is interposed aninteriorly-threaded washer c. The main body portion of the post 0 ispreferably rectangular in shape, and upon two opposite faces thereof areformed deep longitudinal grooves or recesses (Z (Z, parallel with andseparated from each other by means of ribs d d of less width than thewidth of post 0. The post projects downwardly at right angles to thetable or bracket (0. The other two plane faces 6 e of the post 0 areprovided with insulation contact-block holders 0 0 se cured thereto bymeans of screws ff, which screws pass through insulated sleeves 3 3,located in the contact-blocks and through the insulated plates g, g, andThe insulated contact-block holder 6 is adapted to have superposed uponits outer face two separate and distinct contact-blocks f and fseparated from each other by the insulating-rib 4, integral with andprojecting from the contact-block holder 6 as shown in Figs. 3 and 9.The opposite block-holder c has superposed thereupon the contact-block fThese contact-blocks are retained in place by means of the screws ff,which pass through apertures in the insulating-plates g g g and throughthe insulatingsleeves 3 3 in the contact-blocks, the threaded ends ofthe screws engaging the post 0. It is to be noted that the method ofarranging the contact-blocks provides a means whereby one contact may beused for both switches, which results in a saving of time, labor, andmaterial in the construction of a double-pole circuit-breaker.

The ribs (Z cl are provided with laterallyextending interiorly-threadedapertures it it,

adapted to receive the threaded ends it it of a plurality ofoppositely-extending parallel rods if 7&2 72, h Laminated contacts 6 t'are slidingly received upon the rods b if, the rods passing throughapertures z" 6, formed through the contacts and forming ways or guidesfor the contacts when the latter are thrown into or out of contact withthe blocks f f f to complete or break the circuit. The laminatedcontacts are each formed of a plurality of longitudinally-slotted platesof substantially V shape in contour, received and clamped between aninner plate j and an outer plate j. The inner plate j extends upwardlybeyond the edge of the laminated contact and is provided with asemicircular recess 5, adapted to embrace the rod 72, to serve as aguiding means during the movements of the contacts t' to retain them inalinement and insure direct and perfect contact with the blocks f f f Acollar 6 is secured to each of these plates which collar is received inthe apertures c" of the contacts and extends therethrough. The outerplates f of the laminated contacts are made heavier in gage than are theinner plates and of greater length. This method of construction confinesthe are to one point, as the plates 7' f, by reason of their greaterlength, will remain in contact with the blocks f f f for a short timeafter the inner plates have been removed therefrom. The contacts aremounted upon insulated spools it it, the ends of which will embrace theplates composing the contacts between them, and these spools arereceived upon the collars 6 6 of the plates 1" 7". Coil-springs t aremounted on the rods if it, between the inner plates j 7" and thedepending post 0, which springs tend to force the contact-plates t' taway from the blocks f f f.

Vertical shafts 7717M, are journaled to rotate in the table or bracket(4. The bracket is provided with bearings m an integral therewith,within which the shafts m m are journaled. These bearings extend bothabove and below the bracket or table a, the portion extending above thetable having a large interiorlythreaded bore, within which anexteriorlythreaded washer n is received and retained in place by meansof a shouldered threaded annular cap 91. This construction forms apacking which, with the packing 2, operates to prevent the escape of theinsulating liquid with which the box 6 is filled. The lower ends ofshafts m m depend some distance into box 0, and these shafts areprovided near their lower ends with recesses o 0, formed therein andadapted to receive and retain the ends 1/ r/ of the contact-springs a a,which springs encircle or pass around the shafts and have the straightportions p thereof bent into such an angle as will permit the free endstohear against the outer surfaces of the laminated contacts, and thesesprings tend to force the contacts into engagement with thecontactblocks.

Switch-arms p p are adjustably secured upon the upper ends of the shaftsm m, above the caps n n, by means of set-screws 1) p" and are capable ofassuming the positions shown by dotted lines 8 in Fig. i when thelaminated contacts are out of engagement with the contact-blocks. Thefree ends of these switch-arms p 1) are provided with grooves orrecesses 1 7, formed laterally of the switcharms, which latter are madethicker at their free ends, as shown in Fig, 13, and rollers o r arejournaled in these slots. Two pairs of bosses s 3- project upwardly fromthe table or bracket to, and these bosses are slotted for the receptionof a pair of latches 9' pivotally secured thereto by the pins 6, passingthrough the sides of the bosses and through the latches 7' r Theselatches diverge from each other at an angle, and at their shorter rearends are provided with integral parallel extensions a, which extensionsmay be chamfered,.as shown in cross-section in Fig. 1:"). The forwardends of the latches 1" 9' are provided with lips or hook-shaped portionsr 1', as shown in Fig. 12, and the latches are normally retained intheir horizontal positions by means of springs a The slots formed in thefree ends of the switch-arms permit the latter to embrace the forwardends of the latches, the rollers a" a" resting directly thereon andoperating to reduce the friction caused by the movement of the arms uponthe latches. The lips 9" 9"" are adapted to normally retain the arms inengagement with the latches.

The shafts m m extend upwardly through suitable perforations 7 7 in thecover 6 and are provided at their outer ends with handles 8 8, wherebythe circuit may be completed or broken manually by rotating the shafts.

When it is desired to force the laminated contacts 2' c' into engagementwith the contactblocks f f 2 f the switch-arms p p are turned inwardlytoward each other, as shown in full lines in Fig. 4:, until the rollersr 1' pass over the lips or hooked portions o r of the latches, whichretain the arms in position against the tension of springs t t. It willbe noted that the outer ends of the hook-shaped portions are curved orrounded to permit the rollers to pass over them and force the pivotedlatches downward against the tension of springs 8 8 which springs returnthe latches to horizontal position after the passage of the rollers r rover the hooked ends r r When the switcharms 10 10 are disengaged fromlatches r r and have assumed the positions shown by dotted lines .9 s inFig. 4:, the springs 0 0 and the laminated contacts t' c" assume thepositions shown by dotted lines in Fig. 3. The springs 0 0 exert apressure against the laminated contacts when the switch-arms are in theposition shown in full lines in Fig. 4 and insure a full and perfectengagement of the contacts with the blocks. When the switch-arms aredisconnected from the latches, the coilsprings t t on the rods 7? hforce the laminated contacts away from the blocks and automaticallybreak the circuit, the pressure of springs 0 0 having been released bythe rotary movement of the shafts m m, to which 7 they are secured, thuscausing a rapid break.

The adjacent ends of the rods 7& if if k are provided with reducedscrew-threaded ends if it, upon which ends are fitted apertured plates kii, abutting against the shoulders formed by the reduced ends, and theseplates are retained in place by means of nuts k [2 the object being toafford an added rigidity to the rods as well as to strengthen and retainthem parallel with each other.

The automatic action of my improved circuit-breaker is attained asfollows: The rectangular frame 0 is secured to depend from .ing post 0by means of ahollow collar-bolt u,

7 the hollow post 0.

55. Q03 of the collar-bolt is received in the bore 9 the inner end ofwhich is threaded to engage the enlarged interiorly-threaded portion uof The opposite end or head of the yoke '0, which bore is provided witha restricted portion or annular shoulder 10, be-

hind which the collar-bolt is received and operates to secure the yoke cto the box 6. A solenoid u is received and held within the yoke c andsurrounding the bore 9 thereof. A tube M5 is received and fitted withinthe bore 9 of the yoke 0, the upper-end of the tube abutting against theannular shoulder 10 and inclosing the head a of the collar-bolt, thebore 9 of the yoke and the bore of the depending post 0' being inalinement with each other. The head of the collar-bolt is conicallyrecessed, as at 11. The lower end of the tube 14 extends some distancebelow the rectangular yoke 0, and an annular eXteriorly-threaded plug 16is received within and engages the internal screw-threads formed in theend of the tube. The plug is also provided with internal screw threadsadapted to receive the threaded thumb-screw if. A core ai -provided witha conical head a, is loosely received within the tube 16 and thethumb-screw is provided with an enlargement 12 at its inner end, whichabuts the core and by means of which the position of the core within thetube is regulated, the enlargement 12 constituting a stop to limit thedownward movement of the core within the tube, said downward movementcaused by the gravitation of the core. The current flowing through thesolenoid operates to magnetize the core a and causes it to move upward,more or less, in the tube 165 toward the upper end of the coil,according to the amount of current flowing therethrough. The upwardmovement of the core will occur only when the flow of the electriccurrent generates a magnetic field strong enough to overcome theattractive force of gravity. The distance between the top of thesolenoid and the core is diminished or increased by means of thethumb-screw u ac cording to the amount of electric current passingthrough the coil. For instance, if the breaker were intended to operateto interrupt the circuit when a comparatively low current is passingthrough the coil the distance between the head u and the top of the coilwould be much less than when the circuit is to be broken as soon as apredetermined and comparatively high current is attained. A suitablegage 15 is located on the depending tube 165, as shown in Fig. 5,whereby the proper adjustment of the core a can be accuratelydetermined. A collar-pin it is loosely and slidingly received in thehollow depending post 0, the head 10 of which collar-pin normally restsupon the table or bracket (4 to limit the downward movement of the pin.The head u is located directly beneath the integral parallel tripextension at of the latches 0' r The lower end of the collar-pin passesthrough the hollow collar-bolt u and into the tube a in position to bestruck by the core a and forced upward. When the amount of currentrequired to furnish power for or to operate any electrical device hasbeen determined, the core a is adjusted in the tube by means of thethumb-screw a to a position wherein any excess of current will cause thecore to rise and contact with the collar-pin it by creating a magneticfield which is stronger than the force of gravity. When this occurs, thehead 20 of the collar-pin engages and forces the ends of theextension-trips zt U of the pivoted latches 1' 0' upward, whichdepresses the forward ends of the latches against the tension of springss 8 which permits the switch arms 10 p to disengage themselves from thelatches and rotating the shafts m m to release the pressure of springs 00 on the laminated contacts 6 5, which are forced away from thecontact-blocks f f f and break the circuit.

A hand-release is also provided. This consists of a pair of studs w 20projecting upward from the table or bracket a and provided with alinedapertures within which is received the bar w, the inner beveled end 10of which is located just behind the ends of the extension-trips a A coilspring w is mounted upon the bar between the studs w 10 one end of whichspring bears against the stud w and the opposite end of which bearsagainst a collar 20*, secured to the bar 20 by means of a pin 10 passingthrough the bar and collar. This construction operates to force the barw away from the extension-trips u the outer end of the bar passingthrough the cover 5 and provided with a handle, as shown in Fig. 4. Vhenit is desired to release the switch-arms 2 1 from the latches, the bar20 is pushed inward, whereupon the beveled end 20 is forced intoengagement with the extension-trips a, which ride up on the bevel,forcing the forward ends of the latches downward against the tension ofthe springs s s and releasing the switcharms.

A modification of the hand-release is shown in Fig. 15, in which abifurcated stud w is secured to the table a by means of a screw, rivet,or other suitable means. Pivotally secured between the limbs of thisstud is an angle-lever w of general angular shape, the front end ofwhich extends beneath the ends of the extension-trips a and is providedwith a leg the lower end of which rests upon the table a and operates tolimit the movement of the lever 00 in that direction. A spring 00suitably secured, has its free end extending beneath the rear end ofthelever and normally tends to retain the leg 0 in contact with thetable a. To an upward projection 00 on the lever 50 is pivotally securedone end of the hand-release rod w, which projects outside the casing orcover Z. From this description, taken in connection with the drawings,it will be understood that a sharp pull on rod 20 will rock the lever 00on its pivot against the tension of spring 00 and cause the forward endof the lever to engage and force the ends a of the extension-tripsupwardly to release the switch-arms. A slight space is left between thelever 00 and the bifurcated stud in order to permit of the rockingmovement of the lever.

The bifurcated blocks f f are secured to a connecting-piece 2, which inturn is connected with a post 2, passing through the bottom of the box 5and in contact with any suitable electrical medium. The post 2 ispartially screw-threaded and is provided with a shouldered collar ,2,the shoulder of which rests upon the box 5. Surrounding the collarexteriorly of the box 5 is a washer z, and secured upon the bolt beneathand in contact with the washer is a packing-ring .2", held tightly inposition by means of a nut a, received upon the threaded portion of thepost. The dividing-plate 4, which separates the contact-blocksf f alsoseparates the connecting-piece .2, the connecting-piece being supportedat either end in the manner above set forth.

It is evident that many changes might be made in the form andarrangement of the parts describedsuch, for instance, as the adjustmentof the core a by means of weights, springs, or other well-knownmechanical expedientswithout departing from the spirit and scope of myinvention, and hence I do not wish to limit myself to the exact featuresherein set forth; but,

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is

l. A circuit-breaker comprising a case, atable secured within the case,the table provided with a depending post, a plurality of bars, the endsof which are removabl y attached to the depending post, contact-blockssecured thereto, laminated contacts slidingly mounted on the lower bars,a guide-plate secured to the inner side of each of the laminatedcontacts, the guide-plates engaging the upper bars, shafts journaled inhearings in the table, arms adjustably secured upon the upper ends ofthe shafts, latches with which the free ends of the arms are adapted toremovably engage, contact-springs secured to the shafts within thecasing, the free ends of which are adapted to engage the laminatedcontacts, tension means mounted on the lower bars and adapted to engagethe laminated contacts in opposition to the contact-springs, the tensionmeans adapted to force the laminated contacts out of engagement with thecontact-blocks when the arms are released from the latches.

2 An automatic magnetic circuit-breaker comprising a casing composed ofupper and lower portions, a table supported between the upper and lowerportions, a hollow post depending from the table, contact-blocks securedthereto, an insulating liquid contained in the lower portion, shaftsjournaled in the table-arms secured to the upper ends of the shafts, aplurality of bars secured to the depending post, laminated contactsslidingly mounted upon the lower bars, contact-springs secured to thelower ends of the shafts, the free ends of the springs adapted toremovably retain the contacts in engagement with the blocks, latchespivotally mounted upon the table, the arms adapted to removably engagethe latches, a yoke secured to the lower portion of the casing andhaving a central aperture therein in alinement with the bore of thedepending post, a tube received in the aperture, a coil surrounding thetube, a core adjustably supported therein,a collar-pin loosely receivedin the bore of the depending post, the head of the collar-pin adapted toengage and move the latches when the core is forced thereagainst wherebyto release the arms and break the circuit.

3. A circuit-breaker comprising a casing, laminated contacts supportedwithin the easing, contact-blocks with which the contacts are adapted tohave removable engagement, resilient means engaging the contacts for retaining them in contact with the blocks, a yoke secured to the case, asolenoid received within the yoke, the core of the solenoid adjustablymounted therein, a collar-pin loosely supported in the casing, the coreadapted to engage and move the collar pin, pivoted latches arranged tobe operated by the collarpin, arms removably held by the latches, andmeans connecting the arms and the resilient means whereby thedisengagement of the contacts and contact-blocks is effected.

4. An automatic magnetic circuit-breaker comprising a casing, a tablesupported therein, a hollow post depending from the table, a pluralityof bars secured to the sides of the depending post, contact-blockssecured to the sides of the depending post, contacts slidingly mountedon the bars, shafts journaled in the table, arms secured to the shafts,the free ends of the arms provided with rollers journaled therein,latches pivotally mounted on the table, the rollers adapted to engageand be removably retained by the latches, a yoke secured to the casing,a solenoid supported therein, the core of the solenoid adjustablymounted in alinement with the bore of the depending post, a collar-pinloosely supported in the bore of the depending post, the head of thecollar-pin adapted to engage the pivoted latches, the core adapted toengage the collarpin, and cause the latter to engage the pivoted latchesreleasing the roller-arms, and manually-operated means for actuating thepivoted latches.

5. An automatic magnetic circuit-breaker comprising a casing, a tablesupported therein, a post depending from the table, the post locatedcentrally of the table and casing, the lower end of the post providedwith an aperture, a hollow collar-bolt removably received in theaperture, and a yoke supported by the collar-bolt.

6. An automatic magnetic circuit-breaker comprising a casing consistingof upper and lower portions, a table secured between the upper and lowerportions, a post depending from the table into the lower portion of thecasing, bars secured to the depending post, contacts slidingly mountedon the bars, blocks insulated from and removably secured to the post,the table and lower portion of the easpost depending from the table,shafts extending into the casing, arms secured to the upper ends of theshafts within the casing, contactsprings secured to the lower ends ofthe shafts, bars secured to the depending post, insulating holderssecured to the sides of the post, contact-blocks received in theholders, contacts slidingly mounted upon the bars, a solenoid securedoutside the casing, a core, a thumbscrew for adjusting the position ofthe core, the core in alinement with the bore of the depending post, acollar-pin loosely received in the hollow post, the end of thecollar-pin adapted to be struck by the core, pivotal latches with whichthe arms are removably connected, the collar portion of the pin restingupon the table beneath the rear ends of the latches, the pin adapted toengage the latches when struck by the core to release the arms.

8. An automatic circuit-breaker comprising a casing, the casingconsisting of upper and lower flanged portions, a table dividing thecasing, the table supported between the flanges of the upper and lowerportions, packing interposed between the table and the lower portion,insulating liquid filling the lower portion of the casing, operatingmechanism located in the lower portion of the casing, a solenoid securedto the casing, and means operated by the action of the solenoid forbreaking the circuit established within the casing.

9. An'automatic circuit-breaker comprising a suitable support, a table,a post depending therefrom, a plurality of pairs of extending parallelbars secured to two sides of the post, insulated contact-blocks securedto the remaining sides of the post, one of the blocks consisting of twosections insulated from each other, insulated contacts slidingly mountedupon the lowermost bars, guiding means secured to the contacts andengaging the uppermost bars, means normally tending to force thecontacts away from the blocks, shafts rotatably supported in the table,means secured to the shafts and adapted to force the contacts intoengagement with the blocks, arms secured to the shafts above the table,pivoted latches supported upon the table, means for normally retainingthe latches in horizontal position, the arms adapted to engage theforward ends of the latches, a solenoid secured to the frame and meansoperated by the solenoid for rocking the latches to release the armstherefrom.

10. An automatic circuit-breaker comprising a support, a table, a postdepending therefrom, insulated contact-blocks secured thereto,slidingly-mounted insulated laminated contacts, means normally tendingto force the contacts away from the blocks, rotatable shafts, armscarried by the shafts and adapted to retain the latter in one position,means carried by the shafts which tend to force the contacts intoengagement with the blocks, means for locking the arms to retain thecontacts in engagement with the blocks, a solenoid and means operated bythe solenoid whereby to cause the release of the arms and permit thefirst-named means to force the sliding contacts away from the blocks.

11. An automatic circuit-breaker comprising a casing, insulatedcontact-blocks located therein, slidingly-mounted insulated contactsadapted to engage the blocks, means for normally forcing the contactsaway from the blocks, revoluble shafts, means carried by the shafts andadapted to force the contacts against the blocks, arms carried by theshafts, pivoted latches engaged by the free ends of the arms, thelatches adapted to normally retain the arms, means for retaining thelatches normally in horizontal position, a solenoid, and means operatedby the solenoid for rocking the latches to release the arms therefrom.

12. An automatic circuit-breaker comprising a casing, insulatedcontact-blocks located therein, slidingly-mounted insulated contactsadapted to engage the blocks, means for normally forcing the contactsaway from the blocks, revoluble shafts, means carried by the shafts andadapted to force the contacts against the blocks, arms carried by theshafts, pivoted latches engaged by the free ends of the arms, thelatches adapted to normally retain the arms, means for retaining thelatches normally in horizontal position, and a hand-release adapted torock the latches to release the arms therefrom.

13. A mechanism for interrupting a circuit comprising a plurality ofisolated stationary contacts, bridges connecting the contacts,suitably-supported movable members independent of the bridges, yieldingmeans carried by the movable members independent of and adapted toengage the bridges to force them against the contacts, mechanism forretaining the movable members in such position as to hold the meanscarried by such movable members against the bridges to retain the latterin engagement with the contacts, and independent automatic means forforcing the bridges away from the contacts when the movable members arereleased, the yielding means and the automatic means cooperating torotate the movable members.

14. An automatic cut-out comprising a suitable support,contact-blocksand rods secured thereto, sleeves slidingly mounted on the rods,

insulating-collars carried by the sleeves, contacts supported on thecollars and adapted to engage the contact-blocks, yielding means fornormally forcing the contacts away from the contact-blocks, meansnormally operating to force the contacts against the contact-blocks,

which the arms engage and by which they are held when the contacts arein engagement with the blocks, and automatically-operated means adaptedto engage the locking means to release the arms and permit the yieldingmeans to force the contacts away from the blocks.

16. A cut-out comprising a suitable support, blocks and guides securedthereto, contacts movably mounted upon the guides, yielding means fornormally forcing the contacts away from the blocks, movable shaftssuitably supported, means on the shafts adapted to engage the contactsto force them against the blocks, arms secured to the shafts, rollers onthe arms, locking means with which the rollers engage and by which theyare held when the contacts are in engagement with the blocks, andautomatically-operated means adapted to engage the locking means torelease the arms and permit the yielding means to force the contactsaway from the blocks.

17. A cut-out comprising asuitable support, blocks and guides securedthereto, contacts movably mounted upon the guides, yielding means fornormally forcing the contacts away from the blocks, movable shaftssuitably supported, means on the shafts adapted. to engage the contactsto force them against the blocks, arms secured to the shafts, lockingmeans with which the arms engage and by which they are held when thecontacts are in engagement with the blocks, the locking means consistingof pivoted latches, enlargements on the ends of the latches behind whichthe arms are received, springs for retaining the latches in their normalposition, and automatically-operated means adapted to engage the lockingmeans to release the arms and permit the yielding means to force thecontacts away from the blocks.

18. A cut-out comprising a suitable support, blocks and guides securedthereto, contacts movably mounted upon the guides, yielding means fornormally forcing the contacts away from the blocks, movable shaftssuitably supported, means on the shafts adapted to engage the contactsto force them against the blocks, arms secured to the shafts, lockingmeans with which the arms engage and by which they are held when thecontacts are in engagement with the blocks, automatically-operated meansadapted to engage the locking means to release the arms and permit theyielding means to force the contacts away from the blocks, and amanually-operated means for engaging the locking means to release thearms.

19. A cut-out comprising asuitable support, blocks and guides securedthereto, contacts movably mounted upon the guides, yielding means fornormally forcing the contacts away from the blocks, movable shaftssuitably supported, means on the shafts adapted to engage the contactsto force them against the blocks, arms secured to the shafts, lockingmeans with Which the arms engage and by which they are held When thecontacts are in engagement With the blocks, automatically operated meansadapted to engage the locking means to release the arms and permit theyielding means to force the contacts away from the blocks, and amanually-operated means for engaging the locking means to release thearms, the manually operated means consisting of a rod adapted to engageand move the locking means and a spring for normally retaining the rodout of engagement With the locking means.

20. A circuit-breaker comprising, in combination With a source ofelectricity, a plurality of isolated contacts in circuit with theelectrical source, a suitably-supported bridge for connecting thecontacts, means normally tending to force the bridge aWay from thecontacts, a rotatable member independent of the bridge, a resilient armcarried by the member, the arm adapted to engage and move the bridgeagainst the contacts, means for locking the rotatable member in one ofits adjusted positions and an automatic releasing means therefor.

Signed at Mansfield, Ohio, this 10th day of March, 1902.

FRANK O. HARTMAN. Witnesses:

JAMES CHESTER Coss, JOSIAH BRINKERHOFF.

